Systems and methods for biasing high fill-factor sensor arrays and the like

ABSTRACT

A high fill-factor photosensor array is formed comprising a P-layer, an I-layer, one or more semiconductor structures adjacent to the I-layer and each coupled to a N-layer, an electrically conductive electrode formed on top of the P-layer, and an additional semiconductor structure, adjacent to the N-layer and which is electrically connected to a voltage bias source. The bias voltage applied to the additional semiconductor structure charges the additional semiconductor structure, thereby creating a tunneling effect between the N-layer and the P-layer, wherein electrons leave the N-layer and reach the P-layer and the electrically conductive layer. The electrons then migrate and distribute uniformly throughout the electrically conductive layer, which ensures a uniform bias voltage across to the entire photosensor array. The biasing scheme in the invention allows to achieve mass production of photosensors without the use of wire bonding.

This is a Division of application Ser. No. 10/740,466 filed Dec. 22,2003. The entire disclosures of the prior application are herebyincorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of Invention

This invention relates generally to devices with rectifying propertiesthat normally work under reverse biasing conditions.

2. Description of Related Art

Devices with rectifying properties, that may normally work under reversebiasing conditions, require the structural ability to include a biasvoltage. Such devices may be multilayered structures withpositively-doped, or P, layers, and negatively-doped, or N, layers. Insome instances, one or several intrinsic, or I, layers, are also part ofthe device. Devices with rectifying properties and that normally workunder reverse bias conditions may have, for instance, PN, NP, NIP orSchottky-junction structures. The related art discussed herein isspecific to PIN photosensors for clarification purposes only, but theprinciples underlined and discussed can also be applied to otherstructural devices with rectifying properties that normally work underreverse biasing conditions.

High fill-factor structures are structures having a continuous topportion, and a pixelated bottom portion that defines a plurality ofpixels or other repeated structures which are often arranged in an arrayor the like. The continuous top portion is often a positively dopedlayer or a transparent, electrically conductive layer. The pixelatedbottom portion is often formed by negatively doped material and a metalcontact layer. Such high fill-factor devices have been widely used inCMOS imagers with, for instance, positive-intrinsic-negative (PIN)photosensors and in flat panel images. One of the differences between ahigh fill-factor sensor array and a conventional sensor array is that,in a conventional sensor array, the top portion and the bottom portionsare both pixelated. In contrast, in a high fill-factor structure, thetop portion is continuous.

For example, PIN photosensors generally include a positively-dopedlayer, or p-type layer, an undoped or intrinsic layer, or I-layer and anegatively-doped layer, or n-type layer. In this configuration, theI-layer is excited by photons when the photosensor is exposed to light.When irradiated by photons, the I-layer generates electron-hole pairsthat separate under the action of the electric field generated by thebuilt-in potential and the supplied reverse bias, and drift through theI-layer. The electrons drift to the N-layer and the holes drift to theP-layer. When the electrons reach the N-layer through drifting, theytravel through the N-layer and reach one or more signal electrodes. Thesignal electrodes then transmit those electrons to one or moredownstream circuits.

When these PIN photosensors are arranged in an array, each individualphotosensor generates an electrical current proportional to the amountof electrons that drift to the portion of the N-layer that is associatedwith that photosensor structure. Since the amount of electrons driftingout of the I-layer depends upon the light intensity that irradiates theI-layer, the amount of electrons that reach the N-layer and travel tothe signal electrodes also depends on the intensity of the light thatirradiates the portion of the I-layer that is associated with thatparticular semiconductor structure. In other words, the amount of chargethat is generated by each individual photosensor depends directly on theintensity of the light irradiating the portion of the I-layer that isassociated with that photosensor. Accordingly, different photosensorsgenerate different charge levels in the same photosensor array asdifferent portions of the I-layer are irradiated by different amounts oflight.

For the electrons to drift through the I-layer and into the N-layer, avoltage bias should be applied to the photosensor structure. The mostcommon technique used to apply this bias voltage to the photosensorstructure is to add an additional transparent conductive electrode inthe form of a layer on top of the P-layer, and to connect thattransparent conductive layer to a voltage source.

The P-layer is thus generally covered by a transparent, electricallyconductive layer. It should be understood that the transparent,electrically conductive layer needs to be transparent at the wavelengthrange of the electromagnetic radiation that the photosensor is designedto sense. In general, this transparent, electrically conductive layerhas no role in transmitting the light intensity signal and should notinterfere with the light intensity signal by altering, for instance, theintensity or the wavelength of the light intensity signal. It shouldfurther be understood that the transparent, electrically conductivelayer should be applied over the entire surface of the photosensor toprovide a uniform distribution of bias voltage over the entirephotosensor array. A uniform distribution of bias voltage ensures thatthe relative number of electrons that drift through the I-layer and tothe N-layer is proportional only to the intensity of light that is beingirradiated on the I-layer, i.e., that it is not due to local differencesin bias voltage across the P-layer or across the I-layer.

U.S. Pat. No. 6,018,187 describes a PIN layer in which a transparentconductive layer, formed over the P-layer, is electrically connected toa bias voltage source.

SUMMARY OF THE DISCLOSURE

One of the problems in high fill-factor structures, such as thephotosensor array described above, that operate under reverse biasconditions, lies in the increased manufacturing effort and correspondingcosts incurred by the need to electrically connect the transparent,electrically conductive layer to the bias voltage source. Thisconnection, generally done by wire bonding, often presents problems inthat it is difficult to reliably bond the wire to the transparentconductive layer. This often occurs because the transparent conductivelayer is generally made, for instance, out of a ceramic, which can bedifficult to wire bond to. Another problem associated with theabove-outlined biasing scheme is that when mass producing photosensors,additional processing steps to connect the transparent, electricallyconductive layer to the bias voltage source are needed. Accordingly,these additional steps and structural features tend to increase theproduction costs when mass producing photosensors and to reduce theyield rate and reliability of the photosensors.

This invention provides devices, systems and methods for biasing asemiconductor structure that operates under reverse biasing conditions.

This invention provides devices, systems and methods for biasing aphotosensor array.

This invention separately provides devices, systems and methods thatavoid connecting a bias voltage to an electrically conductive layerusing a wire bond.

This invention separately provides devices, systems and methods that useone or more additional semiconductor structures to bias thesemiconductor device operating under reverse bias conditions.

This invention separately provides systems and methods that use the sameprocessing steps, used to form the semiconductor device operating underreverse bias conditions, to form a semiconductor structure of thesemiconductor device that is usable to bias the semiconductor deviceoperating under reverse bias conditions.

In various exemplary embodiments of this invention, the additionalsemiconductor structure is a semiconductor structure selected from thesemiconductor structures that are part of the semiconductor deviceoperating under reverse bias conditions.

In various exemplary embodiments of the devices, systems and methodaccording to this invention, the electrically conductive layer isconnected to a voltage source through one or more additionalsemiconductor structures that are part of the same device as the deviceelements of the semiconductor device operating under reverse biasconditions. The additional semiconductor structures are formed by addingone or more units of the semiconductor device. For example, for a PINphoto sensor, the additional semiconductor structure comprises anN-layer and an underlying signal electrode which, in conjunction withthe I-layer and the P-layer of the PIN photosensor, constitute one ormore additional semiconductor structures added to the device carryingthe photosensor array.

In various exemplary embodiments of the devices, systems and methodsaccording to this invention, when a bias voltage is applied to one ormore of the additional semiconductor structures, the bias voltage passesthrough the additional semiconductor structure to the common electrode.For example, in forward-biased PIN diodes, the N-layer of thatsemiconductor structure will become charged, and electrons willeventually drift out of the N-layer, through the I-layer, and reach theP-layer. Since the transparent, electrically conductive layer isconductively coupled to the P-layer, the electrons coming from theN-layer will propagate in the transparent, electrically conductivelayer. Upon reaching the electrically conductive layer, the electronsmigrate and distribute uniformly throughout the electrically conductivelayer. The uniform distribution of electrons in the electricallyconductive layer contributes to ensuring a uniform bias voltage isapplied to the entire semiconductor device.

In various exemplary embodiments of the systems, methods and devicesaccording to this invention, the electrically conductive electrode maybe a transparent, electrically conductive oxide. In various exemplaryembodiments of this invention, the transparent, electrically conductiveoxide may be formed using indium titanium oxide (ITO). The transparent,electrically conductive oxide may be formed using a known orlater-developed conductive oxide that is transparent at wavelengths tobe sensed.

In various exemplary embodiments of the systems, methods and devicesaccording to this invention, a negative feedback circuit is added to thesemiconductor device, connected in series to the one or more additionalsemiconductor structures to counter the dynamic resistance of the one ormore additional semiconductor structures, should the dynamic resistanceof the one or more additional semiconductor structures become too high.

In various exemplary embodiments of the systems, methods and devicesaccording to this invention, a guard ring structure is added to thesemiconductor device to trap any dark current that may arise from excesscharge created by the bias voltage in the vicinity of the one or moreadditional semiconductor structures and that would affect any nearbyelements of the semiconductor device.

In various exemplary embodiments of the systems, methods and devicesaccording to this invention, the one or more additional semiconductorstructures are located at a distance sufficiently far from the nearestelements of the semiconductor device so that any dark current that mayarise because of the excess charge in the vicinity of the one or moreadditional semiconductor structures is dampened by the distance betweenthe additional semiconductor structures and the closest elements of thesemiconductor device.

These and other features and advantages of various exemplary embodimentsof systems and methods according to this invention are described in, orare apparent from, the following detailed description of variousexemplary embodiments of the systems and methods according to thisinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

Various exemplary embodiments of the systems and methods of thisinvention will be described in detail, with reference to the followingfigures, wherein:

FIG. 1 shows the structure and biasing scheme of a conventional highfill-factor photosensor array;

FIG. 2 shows an equivalent circuit for the high fill-factor photosensorarray shown in FIG. 1;

FIG. 3 shows a first exemplary embodiment of a photosensor device thatincludes a biasing structure according to this invention;

FIG. 4 shows an equivalent circuit for the second exemplary embodimentof a photosensor device that includes a biasing structure and additionalcircuit elements as shown in FIG. 3;

FIG. 5 shows a photosensor device that includes a feedback control loopaccording to various exemplary embodiments of this invention;

FIG. 6 shows a third exemplary embodiment of a photosensor device andadditional structural elements according to this invention;

FIG. 7 shows an equivalent circuit for the third exemplary embodiment ofthe photosensor device shown in FIG. 6;

FIG. 8 shows a fourth exemplary embodiment of a photosensor device thatincludes a biasing structure and additional circuits and structuralelements according to this invention; and

FIG. 9 is a graph showing current v. voltage circuits for a photosensorarray using a conventional biasing scheme and for a photosensor devicethat incorporates one exemplary embodiment of the biasing structureaccording to this invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The following detailed description of various exemplary embodiments ofthe high fill-factor devices that have a rectifying function and/oroperate under reverse biasing conditions according to this invention mayrefer to one specific type of system, a PIN photosensor, for sake ofclarity and familiarity. However, it should be appreciated that theprinciples of this invention, as outlined and/or discussed below, can beequally applied to any known or later-developed high fill-factor deviceand/or to any known or later-developed devices that have a rectifyingfunction and/or that operate under reverse biasing conditions, such asNP structures, PN structures, NIP structures, Schottky-junctionsstructures, or any other structures, beyond the PIN photosensorspecifically discussed herein.

Typically, a high fill-factor photosensor array includes a P-layer, anI-layer, a patterned N-layer, one or more signal electrodes adjacent andelectrically connected to the patterned N-layer portions and atransparent, electrically conductive layer formed on top of the P-layer.A signal electrode and corresponding portions of each of the patternedN-layer, the I-layer, and the P-layer combine to form a semiconductorstructure, such as, for example, a diode. In various exemplaryembodiments according to this convention, one or more additionalsemiconductor structures, such as, for example, forward-biased diodes,are disposed among the other semiconductor structures in the photosensorarray and are electrically connected to a bias voltage source. The biasvoltage applied to the one or more additional semiconductor structurescharges the photosensor array, where electrons leave the N-layer, travelthrough the I-layer and reach the P-layer and the transparent,electrically conductive layer. The electrons then migrate, from theportion of the P-layer associated with the one or more additionalsemiconductor structures into, and distribute uniformly throughout, thetransparent, electrically conductive layer. This uniform distribution ofthe charge in the transparent, electrically conductive layer ensures auniform bias voltage applied to the photosensor array.

FIG. 1 illustrates a conventional high fill-factor photosensor array 100that uses a conventional structure to apply the bias voltage to theP-layer. The photosensor array 100 includes an I-layer 120, formed, forexample, of silicon, sandwiched between a P-layer 110 and an N-layer130. A transparent, electrically conductive layer 140, comprising, forinstance, indium titanium oxide (ITO), is formed on or over the P-layer110 to allow the application of a bias voltage to the photosensor array100. The transparent, electrically conductive layer 140 should betransparent to any irradiation wavelength to which the photosensor 100is designed to be sensitive. In order to apply the bias voltage, themost generally used technique is to electrically connect thetransparent, electrically conductive layer 140 to a voltage source 160via a conductive wire or lead 150.

In the photosensor array 100, in operation, the I-layer 120 isirradiated by a radiation source, and consequently generates electronsdue to the irradiation, which drift out of the I-layer 120 and reach theN-layer 130. When the electrons reach the N-layer 130, they travelthrough the N-layer 130 and reach the underlying signal electrodes 135.When the electrons reach the underlying signal electrodes 135, theunderlying signal electrodes 135 generate an electrical current which istransmitted to, for instance, an underlying CMOS circuit.

In the context of a two-dimensional array, each underlying signalelectrode 135 and its corresponding N-layer 130, I-layer 120 and P-layer110, correspond to a semiconductor structure 170, such as, for example,a single pixel diode. Accordingly, each single semiconductor structure170, when irradiated, generate an electrical current in response to theradiation which reaches the portion of the P-layer 110 that isassociated with that particular semiconductor structure 170. Theamplitude of the electrical current generated by the semiconductorstructure 170 is proportional to the intensity of the light irradiatingthe portion of the P-layer 110 associated with that individualsemiconductor structure 170, since the amount of electrons reaching theunderlying signal electrode 135 and coming from the P-layer 110 dependson the intensity of the irradiating light. Accordingly, differentsemiconductor structures 170 may generate electrical currents ofdifferent intensities when the intensity of the irradiating light isnon-uniform across the P-layer 110 and across the different portions102-106 of the photosensor 100 that are associated with differentsemiconductor structures 170. Each semiconductor structure 170represents a single pixel in the photosensor array, which represents asingle pixel in an image generated as a result of exposing thephotosensor 100 to radiation.

FIG. 2 shows an equivalent circuit for the high fill-factor photosensorarray 100 shown in FIG. 1. The bias voltage source 160 is shownconnected to the semiconductor structures 170 through a commonelectrode, i.e., the transparent, electrically conductive layer 140.

FIG. 3 shows one exemplary embodiment of a high fill-factor photosensorarray 200 according to this invention. In the photosensor array 200shown in FIG. 3, the I-layer 220 generates electrons when irradiated bylight. The electrons travel by drifting out of the I-layer 220 and reachthe N-layer 230. The N-layer 230 transmits the electrons to theunderlying signal electrode 235 of a particular semiconductor structure270 and an electrical current is generated. This electrical current istransmitted to an underlying circuit.

In various exemplary embodiments according to this invention, thetransparent, electrically conductive layer 240, provided on top of theP-layer 210, is not electrically charged by a wire connected to avoltage bias source. Rather, the transparent, electrically conductivelayer 240 is charged by an additional semiconductor structure 280 of thehigh fill-factor photosensor array 200 that is connected to a voltagebias source 260. In various embodiments of this invention, the biasvoltage applied by the voltage bias source 260 to the additionalsemiconductor structure 280 causes electrons to drift through theI-layer 220 and reach the portion of the P-layer 210 associated with theadditional semiconductor structure 280. These drifting electrons thenmigrate from the P-layer portion of the additional semiconductorstructure 280 into the transparent, electrically conductive layer 240.This process charges the transparent, electrically conductive layer 240.Since the electrons uniformly distribute throughout the transparent,electrically conductive layer 240, the transparent, electricallyconductive layer 240 becomes uniformly charged. The charging of thetransparent, electrically conductive layer 240 is merely accomplished byintroducing one or more additional semiconductor structures 280, suchas, for example, forward-biased diodes, into the photosensor array,provided that the additional semiconductor structures 280 are connectedto a bias voltage source 260.

Accordingly, since the bias voltage is applied by the additionalsemiconductor structure 280, and not by an electrical wire bonded to thetransparent, electrically conductive layer 240, this exemplaryembodiment of the high fill-factor photosensor array 200 according tothis invention avoids using wire bonding, and hence eliminates the needfor additional processing and manufacturing steps during mass productionof the photosensor array 200.

FIG. 4 shows an equivalent electrical circuit for the high fill-factorphotosensor array 200. In contrast to the equivalent circuit illustratedin FIG. 2, in the high fill-factor photosensor array 200, as shown inFIGS. 3 and 4, the voltage bias source 260 is connected to thetransparent, electrically conductive layer 240 by the additionalsemiconductor structure 280.

In various exemplary embodiments of the high fill-factor photosensorarray 200 according to this invention, several additional semiconductorstructures 280 can be used in the photosensor array 200 to connect thevoltage bias source 260 to the transparent, electrically conductivelayer 240.

FIG. 5 shows a second exemplary embodiment of a high fill-factorphotosensor array 300 according to this invention. As illustrated inFIG. 5, in the high fill-factor photosensor array 300, a negativefeedback loop 350 is added to the electrical circuitry of the highfill-factor photosensor array 300. This negative feedback loop 350 canbe used to reduce the effective resistance of the one or more additionalsemiconductor structures 380. Although the effective resistance of theone or more additional semiconductor structures 380 is generally small,in the cases where the effective resistance of the one or moreadditional semiconductor structures 380 is not sufficiently small, i.e.,is too large, the negative feedback loop 350 adjusts the output thatdrives the one or more additional semiconductor structures 380 to keep aconstant voltage applied to the transparent, electrically conductivelayer 340.

The negative feedback loop 350 adjusts the output by reducing theeffective resistance of the additional semiconductor structure 380 to anegligible value. It should be appreciated that the effective resistanceof the diode may interfere with the change in potential resulting fromirradiating the photosensor array. As a result, this change in theeffective resistance could cause inconsistency in response from thephotosensor array. Accordingly, by adding the negative feedback loop350, the effective resistance of the additional semiconductor structure380 has substantially no impact on the performance of the photosensorarray 300. In various exemplary embodiments according to this invention,the feedback loop 350 includes an operational amplifier 390, a source ofcurrent 392 and a sensing diode 391, which can all be embedded in,and/or formed using, the semiconductor substrate.

In various exemplary embodiments according to this invention, theadditional semiconductor structure 280 is placed sufficiently far fromthe closest semiconductor structure 270 to avoid generating larger darkcurrents in the vicinity of the additional semiconductor structure 280that negatively impact the operation of any of the semiconductorstructures 270 through accidentally charging the N-layer. In typicalphotosensor structures, dark currents, which result from accidentalelectronic discharges from the semiconductor structures, may appear.These dark currents may be enhanced by the presence of a highly chargedadditional semiconductor structure 280, and may create unwantedelectronic discharges near the semiconductor structures 270 located inthe vicinity of the charged additional semiconductor structure 280.Accordingly, in various exemplary embodiments according to thisinvention, the one or more additional semiconductor structures 280 arelocated at a distance sufficiently far from at least one semiconductorstructure 270 to preclude the formation of dark currents that are ableto negatively affect such neighboring semiconductor structures 270. Invarious exemplary embodiments according to this invention, a distancesufficiently far from any semiconductor structure 270 will typically beseveral times the thickness of the semiconductor stack.

FIG. 6 shows a third exemplary embodiment of a high fill-factorphotosensor array 200 according to this invention. As illustrated inFIG. 6, in various exemplary embodiments according to this invention, aguard ring 450 is provided between the additional semiconductorstructure 480 and neighboring semiconductor structures 470. The guardring 450 tends to trap any dark current that may be created by thecharged additional semiconductor structure 480 and that may adverselyaffect any neighboring semiconductor structures 470. In variousexemplary embodiments according to this invention, the guard ring 250 isgrounded, and traps any dark currents generated by the additionalsemiconductor structures 480. As illustrated in FIG. 6, the guard ring450 is located between one or more of the one or more additionalsemiconductor structures 480 and the adjacent semiconductor structures470, and tends to prevent any dark currents from spilling over to thesemiconductor structures 470. Furthermore, adding the guard ring to thehigh fill-factor photosensor array 400 does not require any additionalprocessing steps in the manufacturing process.

FIG. 7 shows an equivalent circuit for the high fill-factor photosensorarray 400 shown in FIG. 6. The guard ring 450 is connected to thesemiconductor structures 470 and the additional semiconductor structures480 through the common transparent, electrically transparent electrode440. The bias voltage source 460 is connected to the additionalsemiconductor structure 480.

FIG. 8 illustrates the electrical circuit corresponding to a fourthexemplary embodiment of a high fill-factor photosensor array 500according to this invention. As shown in FIG. 8, the high fill-factorphotosensor array 500 includes both a negative feedback loop 550 and aguard ring 555. The negative feedback loop 550 reduces the effectiveresistance of the additional semiconductor structure 580, while theguard ring 555 reduces the dark current generated by the additionalsemiconductor structure 580. In various exemplary embodiments, thecombination of the guard ring 555 and the negative feedback loop 550enhances the performance of the photosensor 500.

FIG. 9 is a graph that shows the result of experimental performancetests comparing a photosensor array that uses incorporating variousexemplary embodiments of additional semiconductor structures accordingto this invention to bias the transparent, electrically conductive layerlayer, relative to photosensor arrays that use more conventional biasingschemes.

The sensor array used to generate the results shown in FIG. 9 is a 500μm by 500 μm high fill-factor type of a-Si:H PIN diode with a guardring. The additional semiconductor structure used to bias thetransparent, electrically conductive layer according to this inventionis a 200 μm by 200 μm diode, and the guard ring is grounded.

FIG. 9 shows that, between applied voltage biases of −5 volts and −0.5volts, there is virtually no difference in the current response betweena high fill-factor photosensor array 200 according to this invention anda more conventional high fill-factor photosensor array 200. In otherwords, the performance of the sensor array that incorporates anadditional semiconductor structure according to this invention issubstantially similar to the performance of a more conventional sensorarray, even though the high fill-factor photosensor array 200 that usesan additional semiconductor structure according to this invention haslower manufacturing costs due to a simpler design and less processingsteps in the manufacturing process.

There is a slight difference in the range −0.5 volts to 0 volts, betweenthe high fill-factor photosensor array 200 that uses an additionalsemiconductor structure according to this invention and a moreconventional sensor. This discrepancy is due to the cut-in voltage ofthe additional semiconductor structure 280. The cut-in voltage is theforward-bias voltage of the additional semiconductor structure 280,i.e., is the point at which the current begins to exponentiallyincrease. As shown in FIG. 9, the cut-in voltage is typically 0.6 to 0.7volts for a silicon diode. If operation of the high fill-factorphotosensor array 200 that uses an additional semiconductor structure inthis region is absolutely necessary, it is possible to include anegative feedback circuit, as illustrated above in FIGS. 5 and 8, tokeep the voltage of the transparent electrically conductive layerconstant.

It should be appreciated that although this invention has been describedin relation to a PIN diode, the systems, methods and structuresaccording to this invention are usable with other structures containingat least a semiconductor layer and at least a common electrode to whicha voltage is applied and where the layers are divided in a plurality ofsemiconductor structures.

Furthermore, while this invention has been described in conjunction withthe exemplary embodiment outlined above, various alternatives,modifications, variations, improvements, and/or substantial equivalents,whether known or that are or may be presently unforeseen, may becomeapparent to those having at least ordinary skill in the art.Accordingly, the exemplary embodiments of the invention, as set forthabove, are intended to be illustrative, not limiting. Various changesmay be made without departing from the spirit and scope of theinvention. Therefore, the invention is intended to embrace all known orlater-developed alternatives, modifications variations, improvements,and/or substantial equivalents.

1. A photosensor device to which a voltage is to be applied, comprising:an intrinsic layer; a positively doped layer; an electrically conductivelayer over the positively doped layer; and a negatively doped layeradjacent to the insulating layer, wherein: the insulating layer, thepositively doped layer, the negatively doped layer and the electricallyconductive layer are functionally divided into a plurality ofsemiconductor structures; and the voltage is applied to a selected oneof the plurality of semiconductor structures.
 2. The photosensor deviceof claim 1, further comprising a circuit reducing an effectiveresistance of the selected semiconductor structure.
 3. The photosensordevice of claim 2, wherein the circuit is a negative feedback loop. 4.The photosensor device of claim 2, further comprising a grounded guardring located between the selected semiconductor structure and at leastone other one of the plurality of semiconductor structures.
 5. Thephotosensor device of claim 1, wherein the electrically conductive layercomprises indium titanium oxide.
 6. The photosensor device of claim 1,further comprising a grounded guard ring that is part of the photosensordevice and that is located between the selected semiconductor structureand at least one other one of the plurality of semiconductor structures.7. The photosensor device of claim 1, wherein the selected semiconductorstructure is located at a distance from the rest of the plurality ofsemiconductor structures.
 8. The photosensor device of claim 1, whereinthe selected semiconductor structure is directly connected to a voltagesource that supplies the voltage.
 9. The photosensor device of claim 1,wherein each semiconductor structure is a diode.
 10. The photosensordevice of claim 1, wherein at least the selected semiconductor structureis a diode.
 11. The photosensor device of claim 1, wherein theelectrically conductive layer is located at least over the positivelydoped layer opposite the intrinsic layer.
 12. The photosensor device ofclaim 1, wherein the positively doped layer is located at least over afirst surface of the intrinsic layer.
 13. The photosensor device ofclaim 1, wherein the negatively doped layer is located at least over asecond surface of the intrinsic layer.
 14. A method for applying avoltage to a photosensor device, the photosensor device comprising: anintrinsic layer; a positively doped layer; an electrically conductivelayer adjacent to the positively doped layer; and a negatively dopedlayer adjacent to the intrinsic layer; wherein the intrinsic layer, thepositively doped layer, the negatively doped layer and the electricallyconductive layer are functionally divided into a plurality ofsemiconductor structures; the method comprising: applying a voltage to aselected semiconductor structure from the plurality of semiconductorstructures; causing drifting of electrons from the negatively dopedlayer, through the intrinsic layer, and into the positively doped layer;and conducting the drifted electrons to the electrically conductivelayer such that the voltage is applied to at least one of the othersemiconductor structures.
 15. The method of claim 14, wherein: thephotosensor device further includes an electrical circuit connected tothe selected semiconductor structure; and the method further comprisesreducing an effective resistance of the selected semiconductor structureusing the electrical circuit.
 16. The method of claim 14, wherein: thephotosensor device further includes a guard ring; and the method furthercomprises grounding dark currents generated by the selectedsemiconductor structure using the guard ring.
 17. The method of claim14, wherein: the photosensor device further comprises an electricalcircuit connected to the selected semiconductor structure; and themethod further comprises reducing an effective resistance of theselected semiconductor structure using an electrical circuit connectedto the selected semiconductor structure.
 18. A multi-elementsemiconductor device to which a voltage is to be applied, comprising: aplurality of layers, including at least a first electrode layer and afirst semiconductor layer, wherein: the plurality of layers arefunctionally divided into a plurality of semiconductor structures, thevoltage being applied to at least one of the semiconductor structures bythe first electrode layer; a selected one of the semiconductorstructures is connected to a voltage source for the voltage, theselected semiconductor structure connecting the voltage source to atleast the first electrode layer through at least the first semiconductorlayer.
 19. The multi-element semiconductor device of claim 18, furthercomprising a circuit reducing an effective resistance of the selectedone of the semiconductor structures.
 20. The multi-element semiconductordevice of claim 18, further comprising a grounded guard ring that ispart of the multi-element semiconductor device and that is locatedbetween the selected one of the semiconductor structures and at leastsome of the other semiconductor structures.